Brown trout density effects on the macroinvertebrate and biofilm communities of headwater streams: a cage experiment

Autores/as

  • Alejandro Alejandro López-de Sancha Institute of Aquatic Ecology, Faculty of Science, University of Girona, 17003, Girona, Spain
  • Romero Roig Catalan Natural History Institution, 08001, Barcelona, Spain
  • Martí Aranyó Institute of Aquatic Ecology, Faculty of Science, University of Girona, 17003, Girona, Spain
  • Anna Vila-Gispert Institute of Aquatic Ecology, Faculty of Science, University of Girona, 17003, Girona, Spain
  • Helena Guasch Blanes Centre for Advanced Studies, 17300, Blanes, Girona, Spain

Resumen

Salmo trutta is a key species of headwater streams that is able to influence the structure of these ecosystems through predation. Populations of this species are being threatened by climate change and hydrological alteration. In order to understand how their disappearance would affect the ecosystem structure of headwater streams, we used cage experiments to analyse different biofilm and macroinvertebrate structural parameters and the biodiversity of their communities under different trout densities. Due to a heavy rain event, our experiment was destroyed on the 10th day, but the role of trout as stream ecosystemic structure drivers was observed, as multiple parameters were modulated by their presence or absence. In the high-density treatments, a significant reduction in the biomass of macroinvertebrate families that fed on biofilms was observed due to direct predation on them, which caused the biofilms to be more autotrophic. A decrease in brown trout population densities could cause cascading trophic effects on the ecosystem structure of headwater streams.

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Publicado

2023-01-10

Número

Sección

Research Paper